From bfebfc9c4a5f1265491a569f7e4927552fb9555f Mon Sep 17 00:00:00 2001
From: Luthics <luthics@foxmail.com>
Date: Tue, 28 Nov 2023 15:20:18 +0800
Subject: [PATCH] =?UTF-8?q?=E6=9B=B4=E6=96=B0=E7=AC=AC=E4=BA=8C=E9=A2=98?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .gitignore |   1 +
 2/main.c   | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 107 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 2/main.c

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..adb36c8
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+*.exe
\ No newline at end of file
diff --git a/2/main.c b/2/main.c
new file mode 100644
index 0000000..97e9e75
--- /dev/null
+++ b/2/main.c
@@ -0,0 +1,106 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int state = 0;
+int v[16];
+char labels[4][16] = {"农夫", "狼", "羊", "菜"};
+int re[16];
+int xx[16];
+int k = 0;
+
+void pt(int state) {
+    for (int i = 0; i < 4; i++) {
+        printf("%d ", (state >> i) & 1);
+    }
+    printf("\n");
+}
+
+int validate_state(int state) {
+    int *f = malloc(sizeof(int) * 4);
+    for (int i = 0; i < 4; i++) {
+        f[i] = (state >> i) & 1;
+        // printf("%d ", f[i]);
+    }
+    // printf("\n");
+    if (!f[1] ^ f[2] && f[0] ^ f[1]) {
+        return 0;
+    } else if (!f[2] ^ f[3] && f[0] ^ f[2]) {
+        return 0;
+    } else {
+        return 1;
+    }
+}
+
+int trans(int x, int undo) {
+    // 0 表示农夫自己过河
+    // 1 表示带狼过河
+    // 2 表示带羊过河
+    // 3 表示带菜过河
+    int tmp_state = state;
+    if (x == 1) {
+        tmp_state = state ^ 3;
+    } else if (x == 2) {
+        tmp_state = state ^ 5;
+    } else if (x == 3) {
+        tmp_state = state ^ 9;
+    } else {
+        tmp_state = state ^ 1;
+    }
+    // pt(state);
+    // printf("%d > ", x);
+    // pt(tmp_state);
+    if (undo) {
+        v[tmp_state] = 0;
+        state = tmp_state;
+        re[--k] = 0;
+        xx[k] = 0;
+        return 1;
+    }
+    if (validate_state(tmp_state) == 0) {
+        return 0;
+    }
+    if (v[tmp_state] == 0) {
+        v[tmp_state] = 1;
+        state = tmp_state;
+        xx[k] = x;
+        re[k++] = state;
+        return 1;
+    }
+    return 0;
+}
+
+void dfs() {
+    // printf(">> %d\n", state);
+    if (state == 15) {
+        for(int i = 0; i < k; i++) {
+            printf("%d > ", xx[i]);
+            pt(re[i]);
+        }
+        printf("\n");
+        return;
+    }
+    if (trans(0, 0)) {
+        dfs();
+        trans(0, 1);
+    }
+    if (trans(1, 0)) {
+        dfs();
+        trans(1, 1);
+    }
+    if (trans(2, 0)) {
+        dfs();
+        trans(2, 1);
+    }
+    if (trans(3, 0)) {
+        dfs();
+        trans(3, 1);
+    }
+}
+
+int main() {
+    // freopen("data.in", "r", stdin);
+    // freopen("data.out", "w", stdout);
+    v[0] = 1;
+    dfs();
+    return 0;
+}
\ No newline at end of file